The peaches of New York

by U. P. Hedrick

The peach suffers more or less from an excessive flow of gum. This gumming is usually a secondary effect of injuries caused by fungi, bacteria, insects, frost, sunscald, and mechanical agencies. There is a good deal of difference in the susceptibilities of varieties to this trouble, sorts having hard wood suffering less than those having soft wood. There is less gumming, too, on trees in soils favoring the maturity of wood, under conditions where sun and frost are not injurious, and, obviously, in orchards where by good care the primary causes of the diseases are kept out.

INSECTS ATTACKING THE PEACH

The peach has its full share of troublesome insects, entomologists listing about forty species, at least half of which are either destructive or annoying in New York. The peach cannot undergo hardships and once it is beset by parasites, it does not prosper. No small part of the peach-grower's time, therefore, is spent in combating the insect-pests of his trees. The several pestiferous species vary greatly in importance, the peach-borer probably holding first place in destructiveness.

The peach-borer (Sanninoidea exitiosa Say) is probably the commonest and is certainly the most ancient enemy of the peach in America. It is found everywhere east of the Rocky Mountains and, since it is a native, its natural host being the wild species of Prunus, it has been a parasite on the peach from the earliest introduction of this fruit. All in all, it is the most destructive insect-pest of the peach, its presence always endangering the life of the tree. All peach-growers know the peach-borer. It is a white, grub-like caterpillar with a yellowish, shield-like head, which lives and feeds in the trunk of the peach just below the surface of the ground, eating out irregular chambers and galleries underneath the bark, sometimes girdling the trees. The pest is easily discovered through the exudation from the infested part of gum mixed with borings and excreta. The borers are found at all times in the summer, usually very small in late summer and autumn but an inch or more in length in early summer. The borer is a larva of a wasp-like moth which lays its eggs in early summer; these hatch in from seven to ten days and the minute borers work their way into the tree. The moth may be deterred somewhat from depositing her eggs by thorough cultivation, mounding the trees and, according to some, by the use of obnoxious coverings or poisonous washes on the trunk. Preventive measures are seldom sufficiently effective, however, and the borers must be destroyed. This is best done by digging them out with a knife or wire—"worming" in the parlance of the peach-grower.

The lesser peach-borer (Sesia pictipes Grote & Robinson) is rather infrequently found infesting the peach in New York. It usually attacks only old trees or those showing injury from freezing or other causes. The borer is much like the common peach-borer, described in the foregoing paragraph, but is smaller, seldom reaching the length of four-fifths of an inch. Unlike the true borer, it infests the trunks as well as the crowns of peach-trees, feeding in much the same way. Fortunately the pest is not common in the State, for it is rather difficult to control, since not only the crown but the trunk must be reached in worming for the pest.

The plum-curculio (Conotrachelus nenuphar Herbst) is sometimes a troublesome pest of the peach. It is a rough, grayish, hump-backed snout-beetle somewhat less than a quarter of an inch in length, an insect so familiar to fruit-growers as hardly to need description. The female beetle pierces the skin of the young peaches and places an egg in the puncture. About this cavity she gouges out a crescent-shaped trench, the puncture and trench making the star and crescent of the Ottoman Empire, hence the common name, "Little Turk." The egg-laying process may be repeated in a number of fruits and from each egg a larva hatches within a week and burrows to the stone, making a wormy fruit. Most of the infested fruits drop. Poisoning with an arsenate is the chief means of combating the pest. Rubbish and vegetation offer hiding places and hibernating quarters for the insects and hence cultivated orchards are most free from curculio. The thin-skinned nectarines are damaged most by the insect but peaches are attacked rather freely. Early peaches suffer much more than late ones from curculio; thus, of standard sorts in New York, Greensboro and Carman are usually injured more or less while Salwey and Chili seldom show a puncture. The plum-orchard is usually the source of supply of curculio and early peaches ought not, therefore, be set with or near plums.

San Jose scale (Aspidiotus perniciosus Comstock) is as harmful to peaches as to any other tree-fruit. The insect is now so well known in all fruit-growing regions as scarcely to need description. It is usually first recognized by its work, evidence of its presence being dead or dying twigs—oftentimes the whole tree is moribund. Examination shows the twigs or trees to be covered with myriads of minute scales, the size of a small pin-head, which give the infested bark a scurfy, ashy look. If the bark be cut or scraped, a reddish discoloration is found. Leaves and fruit as well as bark are infested, the insidious pest, however, usually first gaining a foothold on the trunk or a large branch. Reproduction is continuous throughout the summer in this climate so that the insects multiply by leaps and bounds. The peach, possibly, succumbs more quickly than any other fruit, three years sufficing for the destruction of a young orchard if the pest be brought in on nursery stock. The rougher-barked, older trees resist longer and suffer less injury. Still, old orchards are irretrievably ruined in one or two seasons of unrestricted breeding. Peach-growers, in common with all fruit-growers, find the lime-sulphur solution applied in the dormant season the most effective spray in combating this insect. There are several insect-enemies of the scale that are valuable allies and entomologists say that the insects seem more susceptible to the climatic condition of the country than formerly but still natural checks are far from sufficient and the peach-grower should quickly attack with the spray-nozzle at the first appearance of scale.

Besides the San Jose there are several other scales more or less abundant in New York orchards, two of which make the peach their favorite host. These are the West Indian peach-scale (Aulacaspis pentagona Targioni) and the Peach-Lecanium (Eulecanium nigrofasciatum Pergande). Neither, however, is very troublesome as far north as New York and both are kept well under control by the treatment for the more common San Jose. The Lecanium is responsible for the discolored, sooty peaches occasionally found in parts of the State; for, though the discoloration is caused by a soot-fungus, the fungus lives in the honey-dew of the scale.

The black peach-aphis (Aphis persicæ-niger E. F. Smith) is sometimes a serious pest in light peach-soils in New York but is not nearly as troublesome here as it is in states having a larger proportion of sandy land since it seems to find life easiest in light, warm soils. The insect is an intensely black, shining louse with brownish legs. It lives underground more than above ground, maintaining itself for most part on the tender roots of newly set or nursery trees, being found only occasionally on shoots and foliage. An expert eye detects the presence of the lice by the sparse and jaundiced foliage of young trees which an untrained eye would say were down with incipient yellows—indeed countless numbers of young trees have been sacrificed to the yellow's pyre when they suffered only from lice on the roots. The pest is easily detected on stock received from nurseries—the chief source of infestation—and the trees may be dipped or fumigated as for San Jose scale, thus completely exterminating the aphids. Good culture and a dressing of some fertilizer will help to carry young orchards through an infestation though treatment to a dose of a pound of ground tobacco stems worked in the soil about the roots may be necessary.

There is, too, a green plant-louse (Myzus persicae Sulzer) more or less common on peaches in the State every season. It is very similar in appearance to the green aphis of the apple and other plants and makes its presence known by much the same effect on the leaves. It works on the underside of the leaves along the veins, causing the leaves to pucker, curl and crinkle much as with leaf-curl. This green louse, however, is seldom numerous or harmful enough on peaches to require treatment. Should treatment be required, no doubt nicotine, now the standard remedy for aphids on foliage, would keep the pest under.